So I tried to compile it and got all sorts of coding and other errors. Fortunately I found another Urban Terror project on Github by undeadzy which was updated recently. So I downloaded this branch and the game worked this time. However, I had serious performance regressions.

You can try this method by following instructions below. They will work with game downloaded from official Urban Terror website. (if you also have performance or other issues, there is another easy method explained below)

Download source code, extract the zip file, open a terminal and go the folder by running cd command.

Run make command

You will now have a new build folder. Inside that you will have another folder with your architecture specific name (I had release-linux-i386)

Now, your original Urban terror game files will have have q3ut4 folder. Copy all .pk3 files from that and paste into q3ut4 folder in release-linux-i386 directory.

Make sure ioUrT file have executable permission and run it to launch the game

There is another easier method which worked for me without any performance regressions. Instructions below: